HEMORRHAGE into a pituitary adenoma is a well-known entity. Causes for this have been reported as roentgen irradiation, hypertension, arteriosclerosis, infarction, and hormone therapy; it has also been reported as a spontaneous occurrence.1,2 We wish to report a case of hemorrhage into a pituitary adenoma which occurred during anticoagulant therapy. Report of a Case A 45-year-old white man was admitted to the medical service of the Hospital of the University of Pennsylvania on April 4, 1963, because of chest pain radiating to his left hand. The medical history was free of significant disease. There were no symptoms suggesting any disorder related to the eyes or endocrine system. On physical examination, blood pressure was 135/85 mm Hg. Examination of the head, eyes, ears, nose, and throat was normal. The chest was clear to auscultation, and there was no cardiomegaly. The cardiac rhythm was regular, and there were no murmurs. The